The present invention relates to improvements in a suction controller for an endoscope which is capable of performing an air supply, water supply or a procedure for inserting operation instruments such as forceps in addition to a suction procedure by way of a channel of the endoscope.
Such a suction controller has been heretofore constructed as shown in FIG. 1. Specifically, a guide tube 5 comprises a first lower tube 3 and a second lower tube 4 both of which are threadedly connected to each other end to end. The guide tube 5 is disposed within an outer tube 1 in such a manner that a space portion 6 is formed between the guide tube 5 and the outer tube 1. A suction tube 2 is connected to the peripheral wall of the outer tube 1 whose lower end is connected to a channel of an endoscope. A slide tube 7 is inserted in the guide tube 5 and is resiliently held by a spring 8 which is interposed between the outer peripheral surface of the slide tube 7 and the inner peripheral surface of the guide tube 5. A support tube 10 is provided through a connecting tube 9 at the lower end of the slide tube 7. A slider 12 having a through-hole 11 through which an operation instrument passes is held by the support tube 10. A communicating hole 13 through which the space portion 6 communicates with the interior of the guide tube 5 is provided through the peripheral wall of the first tube 3. A cap 14 is mounted on the upper end of the outer tube 1. The cap 14 has a holding hole 15 through which the upper end of the guide tube 5 communicates with the exterior and an air hole 16 through which the space portion 6 communicates with the open air.
With the above-noted arrangement, suction of mucus or filth in a coeliac cavity can be effected by blocking the holding hole 15 and the air hole 16 with a finger. When both holes 15 and 16 are blocked, the suction path previously extending from air hole 16 to space portion 6 to the suction tube 2 is now changed to extend through the channel on the coeliac cavity as shown with an arrow a in FIG. 1, so that mucus or filth in the coeliac cavity can be drawn into the suction tube 2. An operation procedure using an operation instrument and a suction procedure can be simultaneously effected by inserting the operation instrument through the slide tube 7 and the through-hole 11 of the slider 12 into the channel and simultaneously blocking the air hole 16 with a finger. Furthermore, a liquid supply procedure can be effected by fitting the tip end of an injector into the slide tube 7 and slidingly pushing the slide tube 7 against the restoring force of the spring 8 to block the communicating hole 13 by the support tube 10 which shifts together with the slide tube 7. Accordingly, the interior of the guide tube 5 is shut off from the space portion 6 so that liquid can be fed from the injector through the channel into a coeliac cavity.
However, according to the conventional arrangement described above, since the support tube 10 which blocks the communicating hole 13 during the liquid supply procedure is slidingly fitted into the guide tube 5, it is impossible to seal the sliding plane of the support tube 10 in a reliable manner. Accordingly, a part of liquid ejected from an injector is drawn in the suction tube 2 through the space portion 6 and thus there is a possibility that the liquid may not be completely fed into a coeliac cavity.